Purpose: Even in the cases of localized prostate cancer, there are a substantial number of patients who undergo endocrine therapy, and their prognosis is affected by the treatment. We evaluated the histological effect of endocrine therapy and analyzed its correlation with prognosis.
Methods and subjects: Seventy-seven cases with localized prostate cancer who underwent maximal androgen blockade (MAB) therapy 1 year or longer were pathologically evaluated using repeat biopsy specimens from November 1994 to October 2001. The relationship between clinical parameters and histological effect in repeat biopsy specimens was examined. Biopsy was conducted mainly by the 6-site systematic method, and the histological effect was judged in accordance with the General Rules for Clinical and Pathological Study of Prostate Cancer (3rd edition). The median re-biopsy and follow-up periods were 13 months and 41 months, respectively.
Results: Using this criteria for the histological effects of anti-cancer treatment, the histological effect of endocrine therapy was most frequently observed in class G3b with 61.0%, and correlations with PSA nadir and initial biopsy positive number before endocrine therapy were observed. After biopsy, radical prostatectomy was performed on 9 patients (endocrine therapy was concurrently performed on 4), endocrine therapy on 67 (intermittent administration on 21), and radiation therapy on 1 (MAB was concurrently performed). Outcomes included PSA failure in 14, of whom 2 died of cancer. Three-year and 5-year PSA-failure free survival rates were 91.1% and 76.3%, respectively. Pathological disease stage in radical prostatectomy specimens was examined by dividing it into class G0-2 and class G0-3. This revealed a significant correlation between histological effect and pathological disease stage (pT2-3). PSA-failure free survival was analyzed in 67 of the 77 patients who underwent endocrine therapy. A significantly large number of PSA-failures occurred in class G0-2. Multivariate analysis revealed that the histological effect alone was the influencing factor in PSA-failure.
Conclusion: A strong histological effect by MAB 1 year or longer after treatment was observed on localized prostate cancer. Evaluation of the histological effect by the present method was considered to be a useful predictor for organ-confined disease after radical prostatectomy and endocrine therapy for PSA-failure.